Study On The Geometry Of Seismic Survey In MH Area Of Junggar Basin

In recent years,with the development of vibroseis technology and inceasing environmental awareness,it was changing from traditional explosive to the environmentally and friendly vibroseis on the seimic survey.however,a lot of noise are caused by the vibroseis.such as mechanical interference,Resonance and so on.Therefor,the high-density technology is used by the artisans of the seimic survey.For Suppressing the interference and improveing the Signal-to-noise ratio,the artisans choose the method of the inceasing the density of the seimic survey,and then the data imaging is improved.the cost of the seimic survey will be increased with improveing of the signal-to-noise ratio by the increaseing of coverage density.The investment of seismic survey needs match with the imaging effect of obtaining the target layer data.the geological task is difficult to completed with too little investment;the investment will be redundant and wasteful when the geological task is completed by the excessive investment.The first problem of this paper is to select suitable coverage density of seimic survey for target layer in MH area.The data of vibroseis and the data of high density explosive in the same location are studied based on the project of Xinjiang Daqing.The geometry of seismic of the vibroseis,including the size of bin,the coverage density,is studied to form a method for optimizing the density of vibroseis based on explosive data.Coverage density is the fold divided by Bin aera.The cost of the survey is basically determined when the coverage density of vibroseis is determined.So the second problem of this paper is to select suitable fold and bin after the coverage density confirmed.Three aspects are studied on this paper.First,it is to jump to the conclusion by comparing the effect of different bin size and the number of coverage from considering the ability of noise suppression.Secondly,the influence of different bin and fold on the accuracy of velocity are studied by actual data.Finally,the optimization technique of the geometry of seismic survey is studied from the point of the imaging resolution.The method of analyzing the resolution based on limited bandwidth and prestack migration is used under the consideration of noise.for selecting the geometry of seismic survey,chooseing the representative diffraction point to analyze diffraction point prestack migration response in the multiple geometrys and limited coverage density.Through this study,it is considered that the coverage density of vibroseis seimic survey area should reach 3 times of the explosive seimic survey in MH.The coverage density of the Permian is not less than 1 million 800 thousand/km~2 for the target layer.The aspect ratio should be no less than 0.5.Bin size is less than or equal to 25m.the higher coverage density is needed if shot factor continues to weaken.